Image forming apparatus

ABSTRACT

Image forming apparatus have a plurality of models including a common control board and different in number of electrical components used. The image forming apparatus includes a wire harness including: a third connector removably connected to a first connector provided to the control board; fourth connectors removably connected to second connectors provided to the electrical components; and a plurality of cables connecting the third connector and the fourth connectors. In all of the plurality of models, cables are connected to pins located at both ends of the third connector. In a model in which the number of the plurality of cables is smaller than the number of pins of the third connector, pins of the third connector to which the plurality of cables are not connected are arranged at a central portion in a longitudinal direction of the third connector or near the central portion.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an image forming apparatus having aplurality of models.

2. Description of the Related Art

Electrical components such as motors and sensors arranged in, forexample, an image forming apparatus are connected to a control board bya wire harness. The wire harness is formed mainly of cables andconnectors. At present, the image forming apparatus has a lineup of aplurality of models such as a high-speed machine, a low-speed machine, afull-color machine, and a monochrome machine. In some cases, the numberof electrical components to be used may be different among a pluralityof models. When different control boards are prepared for the pluralityof models, management costs in a factory or a service may increase.Moreover, in a case of assembling a plurality of models on the sameassembly line in a factory, when different control boards are preparedfor the plurality of models, the control boards may be mistakenlymounted to an incorrect model, which may result in production rework atthe time of assembly. In view of the above-mentioned circumstances, inJapanese Patent Application Laid-Open No. H05-172390, there is disclosedstandardization of control boards for a plurality of models.

The number of electrical components to be used may be larger in ahigh-speed machine than that in a low-speed machine, or may be larger ina full-color machine than that in a monochrome machine. Selection of thenumber of connector pins of the control board is conducted based on thenumber of connector pins of a model having a larger number of electricalcomponents. Thus, a connector of a model having a smaller number ofelectrical components may have unoccupied connector pins to which nocable is connected. When the connector has unoccupied pins, at the timeof inserting and removing cables by hand, the cables cannot be insertedand removed straight with respect to a mating connector. Thus, in somecases, the connector is obliquely inserted and removed. In such a case,there is a fear in that the cables are not properly inserted or may bendpins of the mating connector. As a result, the connector is not properlyconnected, which may cause an error.

SUMMARY OF THE INVENTION

In view of the above-mentioned circumstances, the present inventionprovides an image forming apparatus which is capable of reducing aninclination of a connector at a time of connecting and removing aconnector of a wire harness with respect to a connector of a controlboard to be used in common to a plurality of models.

According to one embodiment of the present invention, there is providedan image forming apparatus comprising: a plurality of conveyance rollersconfigured to convey a sheet; an image forming unit configured to forman image on the sheet; a first motor; a second motor; a control boardconfigured to control the first motor to rotate a first roller among theplurality of conveyance rollers, and control the second motor to rotatea second roller and a third roller among the plurality of conveyancerollers; a first connector provided to the control board; secondconnectors provided to the first motor and the second motor,respectively; and a wire harness including: a third connector, which isprovided at one end portion of the wire harness, and is removablyconnected to the first connector; and fourth connectors, which areprovided at an other end portion of the wire harness, and are removablyconnected to the second connectors; and a plurality of cables connectingthe third connector and the fourth connectors, wherein a number of theplurality of cables is smaller than a number of pins of the thirdconnector, wherein a first cable of the plurality of cables is connectedto a first pin among the pins of the third connector, wherein a secondcable of the plurality of cables is connected to a second pin among thepins of the third connector, and wherein a third pin, among the pins ofthe third connector, to which any of the plurality of cables is notconnected is arranged between the first pin and the second pin.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view for illustrating an image forming apparatus.

FIG. 2 is a block diagram for illustrating the image forming apparatus.

FIG. 3A and FIG. 3B are illustrations of modes of connection between thecontrol board and motors.

FIG. 4A and FIG. 4B are wiring diagrams for illustrating wiring betweena connector of the control board and connectors of conveyance motors.

FIG. 5A, FIG. 5B, and FIG. 5C are illustrations of cables connected topins of the connector.

DESCRIPTION OF THE EMBODIMENTS

(Image Forming Apparatus)

Now, an embodiment will be described with reference to the drawings.First, a configuration of an image forming apparatus 100 is describedwith reference to FIG. 1. FIG. 1 is a sectional view for illustratingthe image forming apparatus 100. The image forming apparatus 100according to this embodiment has a plurality of models. The imageforming apparatus 100 includes a user interface (hereinafter referred toas “UI”) 126 which is to be operated by a user. In this embodiment,illustration is given of an electrophotographic full-color image formingapparatus 100 having such a configuration that toner containers 130Y,130M, 130C, and 130K for four colors storing developers (hereinafterreferred to as “toners”) to be supplied to developing devices 105 aremountable and dismountable with respect to the image forming apparatus100.

The image forming apparatus 100 includes process cartridges 103Y, 103M,103C, and 103K, which are arranged at constant intervals on asubstantially horizontal straight line and serve as image forming units.The process cartridges 103Y, 103M, 103C, and 103K are mountable anddismountable with respect to the image forming apparatus 100. Theprocess cartridges 103Y, 103M, 103C, and 103K are configured to form ayellow image, a magenta image, a cyan image, and a black image,respectively. The characters Y, M, C, and K added to the referencesymbols represent yellow, magenta, cyan, and black, respectively. In thefollowing description, the characters Y, M, C, and K added to thereference symbols are omitted when not required. The four processcartridges 103 have the same structure except for the colors of thetoners.

Drum-type electrophotographic photosensitive members (hereinafterreferred to as “photosensitive drums”) 104Y, 104M, 104C, and 104Kserving as image bearing members are provided to the process cartridges103, respectively. A primary charging device 109, the developing device105, and a drum cleaner device 112 are arranged around each of thephotosensitive drums 104. At positions opposed to the photosensitivedrums 104 over an intermediate transfer belt 101, there are arrangedprimary transfer rollers 114, respectively. Below the photosensitivedrums 104, there is provided an optical scanning device (hereinafterreferred to as “exposure device”) 108. The exposure device 108 includeslaser light-emitting elements configured to emit laser beams inaccordance with time-series electric digital pixel signals correspondingto image information pieces for colors to be input. The exposure device108 is configured to emit a laser beam to a corresponding one of thephotosensitive drums 104 through a space defined between correspondingones of the primary charging devices 109 and the developing devices 105.The exposure device 108 forms electrostatic latent images in accordancewith the image information pieces for colors on corresponding surfacesof the photosensitive drums 104 having been uniformly charged by theprimary charging devices 109.

The photosensitive drums 104 each include a drum base member made ofaluminum and a layer of an organic photoconductor (OPC) formed on thedrum base member. The photosensitive drums 104 are each rotated at apredetermined process speed by a driving device (not shown) describedlater. The primary charging devices 109 serving as primary chargingunits are configured to uniformly charge the surfaces of thephotosensitive drums 104 to a predetermined electric potential having anegative polarity by a charging bias applied from a charging bias powersupply (not shown). The developing devices 105 store toners and areconfigured to develop the electrostatic latent images formed on thephotosensitive drums 104 as toner images (form visible images) bycausing toners of corresponding colors to adhere to the photosensitivedrums 104. The primary transfer rollers 114 serving as primary transferunits are provided inside an intermediate transfer belt unit 115 so asto be opposed to the photosensitive drums 104 and are urged toward thephotosensitive drums 104, respectively. The drum cleaner devices 112serving as cleaning units include respective cleaning blades configuredto remove residual toners, which remain on the surfaces of thephotosensitive drums 104 after the primary transfer, from thephotosensitive drums 104.

The intermediate transfer belt unit 115 includes a drive roller 116 anda gear (not shown). The drive roller 116 serves also as a secondarytransfer opposing roller. The gear is provided on a shaft of the driveroller 116. The gear meshes with a drive gear provided to a main body ofthe image forming apparatus 100, and the drive roller 116 is rotated bythe drive gear. The drive roller 116 is provided so as to be opposed toa secondary transfer roller 117 over the intermediate transfer belt 101and defines a secondary transfer portion between the secondary transferroller 117 and the intermediate transfer belt 101. An optical sensor 140configured to read density-detection toner patches orcolor-misregistration-correction toner patches formed on theintermediate transfer belt unit 115 is provided on an upstream side ofthe secondary transfer portion. On a downstream side of the secondarytransfer roller 117 in a conveyance direction of a recording medium,there is provided a fixing device 127 including a fixing roller 118 anda pressure roller 119 in a vertical-path configuration.

(Image Forming Operation)

Next, an image forming operation performed by the image formingapparatus 100 is described. Respective image forming processes performedby the four process cartridges 103Y, 103M, 103C, and 103K are the same.When an original reading device 120 reads an image of an original andoutputs an image formation start signal, the surfaces of thephotosensitive drums 104 rotated at the predetermined process speed areuniformly charged to a negative polarity by the primary charging devices109. The exposure device 108 emits laser beams from the laserlight-emitting elements in accordance with time-series electric digitalpixel signals for corresponding colors output from the original readingdevice 120 to form electrostatic latent images on the surfaces of thephotosensitive drums 104. The developing devices 105 to which adeveloping bias having the same polarity as the charge polarity(negative polarity) of the photosensitive drums 104 has been appliedcause toners to adhere to the electrostatic latent images formed on thephotosensitive drums 104, to thereby form visible images as tonerimages. The toner images formed on the photosensitive drums 104 aretransferred to the intermediate transfer belt 101 by the primarytransfer rollers 114 to which a primary transfer bias (polarity oppositeto that of toners (positive polarity)) has been applied.

The yellow toner image, the magenta toner image, the cyan toner image,and the black toner image formed by the process cartridges 103Y, 103M,103C, and 103K, respectively, are sequentially transferred insuperimposition onto the intermediate transfer belt 101. As a result, afull-color toner image is formed on the intermediate transfer belt 101.Residual toners, which remain on the photosensitive drums 104 after theprimary transfer, are scraped off and collected by the cleaner bladesprovided to the drum cleaner devices 112. The full-color toner imageformed on the intermediate transfer belt 101 is moved to the secondarytransfer portion defined between the drive roller 116 and the secondarytransfer roller 117.

Meanwhile, a feeding cassette 121 configured to store recording media(sheets) is provided at a lower part in the image forming apparatus 100.Besides paper such as plain paper and thick paper, examples of therecording media include those made of a freely selected material,specifically, special paper such as coated paper, a plastic film for anoverhead projector, and cloth, and those having a freely selected shape,specifically, an envelope and an index sheet. Moreover, a multi-feedingtray 122 on which recording media are placed is provided at a sideportion of the image forming apparatus 100. The recording medium fedfrom the feeding cassette 121 or the multi-feeding tray 122 is conveyedto registration rollers 123 through a conveyance path formed so as toextend in a substantially vertical direction. Specifically, therecording medium stored in the feeding cassette 121 is picked up by afeeding roller 813 and is then fed to a first vertical path roller 811.The recording medium is conveyed by the first vertical path roller 811to a second vertical path roller 812 and is thereafter conveyed by thefirst vertical path roller 811 and the second vertical path roller 812to the registration rollers 123. Moreover, the recording medium placedon the multi-feeding tray 122 is picked up by a multi-feeding roller 814and is then fed to the first vertical path roller 811. The recordingmedium is conveyed by the first vertical path roller 811 to the secondvertical path roller 812 and is thereafter conveyed by the firstvertical path roller 811 and the second vertical path roller 812 to theregistration rollers 123.

The registration rollers 123 convey the recording medium to thesecondary transfer portion in such a manner that a leading edge of thefull-color toner image formed on the intermediate transfer belt 101 anda leading edge of the recording medium match each other at the secondarytransfer portion defined between the drive roller 116 and the secondarytransfer roller 117. The secondary transfer roller 117 to which thesecondary transfer bias (polarity opposite to that of toners (positivepolarity)) has been applied collectively transfers the full-color tonerimage formed on the intermediate transfer belt 101 to the recordingmedium. Residual toner, which remains on the intermediate transfer belt101 after the secondary transfer, is scraped off and collected by atransfer cleaning device 107.

The recording medium having the full-color toner image transferredthereto is conveyed to the fixing device 127. The full-color toner imageis heated and pressurized at a fixing nip defined between the fixingroller 118 and the pressure roller 119 of the fixing device 127 to bethermally fixed on a surface of the recording medium. As a result, afull-color image is formed on the surface of the recording medium. Therecording medium having the full-color image formed thereon is deliveredby first delivery rollers 124 onto a delivery tray 125. In such amanner, the series of processes of the image forming operation isterminated.

(Control Unit)

Next, with reference to FIG. 2, a control unit 200 configured tointegrally control the image forming apparatus 100 is described. FIG. 2is a block diagram for illustrating the image forming apparatus 100. Thecontrol unit 200 is a control board to be used in common to all of theplurality of models of the image forming apparatus 100. The control unit200 has functions to drive loads in the image forming apparatus 100,collect and analyze information pieces given by sensors 214, andexchange data with the UI 126. The control unit 200 includes a centralprocessing unit (hereinafter referred to as “CPU”) 201 a to perform thefunctions described above. The control unit 200 further includes aread-only memory (hereinafter referred to as “ROM”) 201 b, arandom-access memory (hereinafter referred to as “RAM”) 201 c, ananalog-digital converter (hereinafter referred to as “A/D”) 203, and ahigh-voltage controller 205. The control unit 200 further includes amotor driver 207, a DC load controller 208, a sensor interface(hereinafter referred to as “sensor IF”) 209, and an AC driver 210.

The CPU 201 a is configured to execute various sequences associated withpredetermined image formation sequences in accordance with a programstored in the ROM 201 b. In such an operation, the RAM 201 c temporarilyor permanently stores rewritable data. The RAM 201 c is configured tostore, for example, a high-voltage setting value set to the high-voltagecontroller 205, various data described later, and image formationcommand information given through the UI 126. The UI 126 is configuredto output information such as a copy magnification and a density settingvalue set by a user to the CPU 201 a. The CPU 201 a outputs informationon a state of the image forming apparatus 100, for example, the numberof images to be formed or whether or not the image formation is beingperformed, occurrence of a j am, and a location of the occurrence of thejam to the UI 126 and presents the information to a user through the UI126.

The image forming apparatus 100 includes an image forming motor 211, atoner supply motor 212, a first vertical path motor 511, a secondvertical path motor 512, a feed motor 513, and a multi-feeding motor514. The image forming motor 211, the toner supply motor 212, the firstvertical path motor 511, the second vertical path motor 512, the feedmotor 513, and the multi-feeding motor 514 are electrically connected tothe motor driver 207. The image forming apparatus 100 further includesDC loads such as a clutch/solenoid (hereinafter referred to as “CL/SL”)(electrical component) 213, and sensors (electrical components) 214 suchas a photo-interrupter and a microswitch. The CL/SL 213 is electricallyconnected to the DC load controller 208. The sensors 214 areelectrically connected to the sensor IF 209. The CPU 201 a controls themotor driver 207 and the DC load controller 208 to drive various motorsand DC loads, to thereby convey the recording medium and drive variousunits. The CPU 201 a acquires detection signals from the sensors 214through the sensor IF 209 to monitor the conveyance of the recordingmedium and the operations of the various units.

The control unit 200 controls the image forming motor 211, the tonersupply motor 212, the first vertical path motor 511, the second verticalpath motor 512, the feed motor 513, and the multi-feeding motor 514through the motor driver 207 based on the detection signals given by thesensors 214. The control unit 200 drives the CL/SL 213 through the DCload controller 208 to smoothly advance the image forming operation. TheCPU 201 a outputs various high-voltage control signals to a high-voltageunit 206 through the high-voltage controller 205. The high-voltage unit206 is configured to allow an appropriate high voltage to be applied tothe primary charging devices 109. The CPU 201 a controls ON/OFF statesof a heater provided in the fixing device 127 through the AC driver 210.The fixing device 127 includes a thermistor 204 configured to measuretemperature inside the fixing device 127. A change in resistance valueof the thermistor 204, which corresponds to a change in temperatureinside the fixing device 127, is converted by the A/D 203 into a voltagevalue and is thereafter input as a digital value to the CPU 201 a. TheCPU 201 a controls the temperature inside the fixing device 127 throughthe AC driver 210 based on temperature data being the digital value.

(Modes of Connection between Control Board and Motors)

Next, with reference to FIG. 3A and FIG. 3B, modes of connection betweenthe motors provided to the image forming apparatus 100 and the controlunit 200 are described. The image forming apparatus 100 has a pluralityof models including the control unit 200 to be used in common and beingdifferent in number of electrical components to be used. FIG. 3A andFIG. 3B are illustrations of modes of connection between the controlunit (control board) 200 and the motors. This embodiment is describedwith an example in which there are given models being different innumber of motors as electrical components to be used depending on theprinting speed of the image forming apparatus 100.

FIG. 3A is an illustration of an arrangement of motors in a first modelof the image forming apparatus 100 capable of printing seventy sheetsper minute. The first vertical path roller 811 is driven by the firstvertical path motor (electrical component) 511. The second vertical pathroller 812 is driven by the second vertical path motor (electricalcomponent) 512. The feeding roller 813 is driven by the feed motor(electrical component) 513. The multi-feeding roller 814 is driven bythe multi-feeding motor (electrical component) 514. The first verticalpath motor 511, the second vertical path motor 512, the feed motor 513,and the multi-feeding motor 514 are mounted on a motor mounting sheetmetal 900. A connector (first connector) 300 is provided to the controlunit 200. A connector 301 is provided to the first vertical path motor511. A connector 302 is provided to the second vertical path motor 512.A connector 303 is provided to the feed motor 513. A connector 304 isprovided to the multi-feeding motor 514. A wire harness 801 connects theconnector 300 of the control unit 200 to the connectors 301, 302, 303,and 304 of the four conveyance motors (first vertical path motor 511,second vertical path motor 512, feed motor 513, and multi-feeding motor514). The control unit 200 controls driving of the four conveyancemotors (first vertical path motor 511, second vertical path motor 512,feed motor 513, and multi-feeding motor 514) through the wire harness801.

FIG. 3B is an illustration of an arrangement of motors in a second modelof the image forming apparatus 100 capable of printing thirty-fivesheets per minute. The first vertical path motor 511, the feed motor513, and the multi-feeding motor 514 are mounted on the motor mountingsheet metal 900. The second model capable of printing thirty-five sheetsper minute is lower in conveyance speed of the recording medium than thefirst model capable of printing seventy sheets per minute. Therefore,torques for driving the first vertical path roller 811 and the secondvertical path roller 812 are sufficiently satisfied with only the motortorque of the first vertical path motor 511. Accordingly, a gearconfiguration is modified, and the first vertical path roller 811 andthe second vertical path roller 812 are driven through a modified gearmechanism with only the first vertical path motor 511. Thus, the secondvertical path motor 512 is not required for the second model capable ofprinting thirty-five sheets per minute. A wire harness 802 connects theconnector 300 of the control unit 200 to the connectors 301, 303, and304 of the three conveyance motors (first vertical path motor 511, feedmotor 513, and multi-feeding motor 514). The control unit 200 controlsdriving of the three conveyance motors (first vertical path motor 511,feed motor 513, and multi-feeding motor 514) through the wire harness802.

(Wire Harness)

FIG. 4A and FIG. 4B are wiring diagrams for illustrating wiring betweenthe connector 300 of the control unit (control board) 200 and theconnectors of the conveyance motors. FIG. 4A is a wiring diagram forillustrating the wire harness 801 of the first model capable of printingseventy sheets per minute. The wire harness 801 has, at one end portionthereof, a connector (third connector) 30 which is connectable andremovable with respect to the connector 300 of the control unit 200. Theconnector 30 is used in common to all of the plurality of models of theimage forming apparatus 100. The connector 300 of the control unit 200includes a plurality of pins. The number of pins of the connector 30 ofthe wire harness 801 is the same as the number of pins of the connector300 of the control unit 200. The wire harness 801 has, at the other endportion thereof, four connectors (fourth connectors) 31, 32, 33, and 34.The connector 31 is removably connected to the connector (secondconnector) 301 of the first vertical path motor 511. The connector 32 isremovably connected to the connector (second connector) 302 of thesecond vertical path motor 512. The connector 33 is removably connectedto the connector (second connector) 303 of the feed motor 513. Theconnector 34 is removably connected to the connector (second connector)304 of the multi-feeding motor 514.

The first vertical path motor 511, the second vertical path motor 512,the feed motor 513, and the multi-feeding motor 514 are driven by themotor driver 207 mounted to the control unit 200. An A-phase signal atthe 1st pin of the connector 30 is connected by a cable 821 to the 4thpin of the connector 31 connected to the connector 301 of the firstvertical path motor 511. An AX-phase signal at the 2nd pin of theconnector 30 is connected by a cable 821 to the 3rd pin of the connector31 connected to the connector 301 of the first vertical path motor 511.A B-phase signal at the 3rd pin of the connector 30 is connected by acable 821 to the 2nd pin of the connector 31 connected to the connector301 of the first vertical path motor 511. A BX-phase signal at the 4thpin of the connector 30 is connected by a cable 821 to the 1st pin ofthe connector 31 connected to the connector 301 of the first verticalpath motor 511.

As illustrated in FIG. 4A, the 5th to 8th pins of the connector 30 areconnected by the cables 821 to the connector 32 connected to theconnector 302 of the second vertical path motor 512. The 9th to 12thpins of the connector 30 are connected by the cables 821 to theconnector 33 connected to the connector 303 of the feed motor 513. The13th to 16th pins of the connector 30 are connected by the cables 821 tothe connector 34 connected to the connector 304 of the multi-feedingmotor 514. In the first model illustrated in FIG. 4A, the cables 821 areconnected to all of the sixteen pins of the connector 30. Thus, onecable of the plurality of cables 821 is connected to the pin (1st pin)located at one end portion of the connector 30, and another cable of theplurality of cables 821 is connected to the pin (16th pin) located atthe other end portion of the connector 30.

In the first model, four conveyance motors at maximum are electricallyconnected to the connector 300 of the control unit 200. However, themaximum number of conveyance motors connected to the connector 300 isnot limited to four. It is only required that the maximum number ofconveyance motors electrically connectable to the connector 300 be threeor more.

FIG. 4B is a wiring diagram for illustrating the wire harness 802 of thesecond model capable of printing thirty-five sheets per minute. The wireharness 802 has, at one end portion thereof, the connector (thirdconnector) 30 which is connectable and removable with respect to theconnector (first connector) 300 of the control unit 200. The connector30 for the first model is used also as the connector 30 for the secondmodel. Thus, the number of pins of the connector 30 of the wire harness802 is the same as the number of pins of the connector 300 of thecontrol unit 200. However, the number of the plurality of cables 822 ofthe wire harness 802 (twelve) is smaller than the number of pins of theconnector 30 (sixteen). The wire harness 802 has, at the other endportion thereof, three connectors (fourth connectors) 31, 33, and 34.The connector 31 is removably connected to the connector (secondconnector) 301 of the first vertical path motor 511. The connector 33 isremovably connected to the connector (second connector) 303 of the feedmotor 513. The connector 304 is removably connected to the connector(second connector) 304 of the multi-feeding motor 514. Thus, one cableof the plurality of cables 822 is connected to the pin (1st pin) locatedat the one end portion of the connector 30, and another cable of theplurality of cables 822 is connected to the pin (16th pin) located atthe other end portion of the connector 30. In the second model, thesecond vertical path motor 512 is not required. Therefore, the number ofcables 822 of the wire harness 802 (twelve in this embodiment) issmaller than the number of pins of the connector 30. The cables 822 arenot connected to the 5th pin, the 6th pin, the 7th pin, and the 8th pinof the connector 30. The 5th pin, the 6th pin, the 7th pin, and the 8thpin of the connector 30 to which the cables 822 are not connected arearranged at a central portion in a longitudinal direction of theconnector 30 or near the central portion.

In the second model, three conveyance motors are electrically connectedto the connector 300 to which four conveyance motors at maximum areconnectable, but the number of conveyance motors connected to theconnector 300 is not limited to three. It is preferred that at least twoconveyance motors be electrically connected to the connector 300.

(Connector)

FIG. 5A, FIG. 5B, and FIG. 5C are illustrations of the cables 821, 822,and cables 823 connected to the pins of the connector 30. FIG. 5A is anillustration of a state in which the cables 821 are connected to all ofthe sixteen pins of the connector 30 in this embodiment. When theconnector 30 is inserted and removed with respect to the connector 300by nipping the portion A of the wire harness 801 with fingers in thisstate, the connector 30 is in a state in which a posture thereof isstable. That is, a position of the connector 30 of the wire harness 801can easily be determined with respect to a surface (hereinafter referredto as “connector surface”) 300 a at a top portion of the connector 300of the control unit 200, thereby being capable of inserting and removingthe connector 30 with respect to the connector 300 in a verticaldirection VD. The ease of inserting and removing the connector 30 isexcellent, and hence the connector 30 can be correctly thrust into theconnector 300, thereby being capable of reliably fitting the connector300 and the connector 30 to each other.

Next, FIG. 5B is an illustration of a reference example. In thereference example illustrated in FIG. 5B, illustration is given of astate in which the cables 823 are not connected to the 13th pin, the14th pin, the 15th pin, and the 16th pin of the connector 30. When theconnector 30 is inserted and removed with respect to the connector 300by nipping the portion C of the wire harness 803 with fingers in thisstate, stress is applied to the 1st to 12th pins of the connector 30,with the result that the connector 30 is brought into a state in which aposture thereof is not stable. Therefore, there is difficulty indetermining a position of the connector 30 of the wire harness 803 withrespect to the connector surface 300 a of the connector 300 of thecontrol unit 200, with the result that the connector 30 is liable to beinserted and removed with respect to the connector 300 in an obliquedirection OD. As a result, at the time of inserting and removing theconnector 30, the pins of the connector 300 may be bent, or theconnector 30 cannot be correctly thrust into the connector 300.

Next, FIG. 5C is an illustration of a state in which the cables 822 arenot connected to the 5th pin, the 6th pin, the 7th pin, and the 8th pinof the connector 30 in this embodiment. When the connector 30 isinserted and removed with respect to the connector 300 by nipping theportion B of the wire harness 802 with fingers in this state, stress isapplied also to the 1st pin and the 16th pin located at both ends of thepin connector 30, and hence the connector 30 is brought into a state inwhich a posture thereof is stable. Thus, similarly to the stateillustrated in FIG. 5A, a position of the connector 30 of the wireharness 802 can easily be determined with respect to the connectorsurface 300 a of the connector 300 of the control unit 200, therebybeing capable of inserting and removing the connector 30 with respect tothe connector 300 in the vertical direction VD. The ease of insertingand removing the connector 30 can be favorably maintained, and hence theconnector 30 can be correctly thrust into the connector 300, therebybeing capable of reliably fitting the connector 300 and the connector 30to each other.

This embodiment has been described with the example of the image formingapparatus 100 having a plurality of models including the control unit200 to be used in common and being different in number of motors aselectrical components to be used. However, this embodiment is applicablealso to an image forming apparatus having a plurality of modelsincluding the control unit 200 to be used in common and being differentin number of sensors 214, CL/SLs 213, solenoids, or switches aselectrical components to be used.

This embodiment has been described with the example in which the firstmodel is a high-speed machine and the second model is a low-speedmachine. However, this embodiment is not limited to this example. Forexample, the first model may be a full-color machine, and the secondmodel may be a monochrome machine. According to this embodiment, withregard to a product having a plurality of models such as a high-speedmachine and a low-speed machine, a full-color machine and a monochromemachine, and the like, even when the control board is standardized, theconnectors can be correctly inserted and removed without degrading theease of inserting and removing the connectors.

According to this embodiment, an inclination of the connector 30 at thetime of connecting and removing the connector 30 of the wire harness801, 802 with respect to the connector 300 of the control unit 200 to beused in common to a plurality of models can be reduced.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2019-040120, filed Mar. 6, 2019, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An image forming apparatus comprising: aplurality of conveyance rollers configured to convey a sheet; an imageforming unit configured to form an image on the sheet; a first motor; asecond motor; a control board configured to control the first motor torotate a first roller among the plurality of conveyance rollers, andcontrol the second motor to rotate a second roller and a third rolleramong the plurality of conveyance rollers; a first connector provided tothe control board; second connectors provided to the first motor and thesecond motor, respectively; and a wire harness including: a thirdconnector, which is provided at one end portion of the wire harness, andis removably connected to the first connector; and fourth connectors,which are provided at an other end portion of the wire harness, and areremovably connected to the second connectors; and a plurality of cablesconnecting the third connector and the fourth connectors, wherein anumber of the plurality of cables is smaller than a number of pins ofthe third connector, wherein a first cable of the plurality of cables isconnected to a first pin among the pins of the third connector, whereina second cable of the plurality of cables is connected to a second pinamong the pins of the third connector, and wherein a third pin, amongthe pins of the third connector, to which any of the plurality of cablesis not connected is arranged between the first pin and the second pin.2. The image forming apparatus according to claim 1, wherein the firstroller rotates to pick-up the sheet.
 3. The image forming apparatusaccording to claim 1, wherein the second roller and the third rollerconvey the sheet along a vertical path.